diff --git a/wmake/rules/General/transform b/wmake/rules/General/transform
index bffe6055c0..3fa0152040 100644
--- a/wmake/rules/General/transform
+++ b/wmake/rules/General/transform
@@ -10,6 +10,7 @@ $(foreach s,$(SUFFIXES),$(eval $(call DEFINE_TRANSFORM,$(s))))
 $(OBJECTS_DIR)/%.dep : %
 	@$(WM_SCRIPTS)/makeTargetDir $@
 	@$(WMAKE_BIN)/wmkdep -I$(*D) $(LIB_HEADER_DIRS) $< | \
-	    sed 's,$(WM_PROJECT_DIR),$$(WM_PROJECT_DIR),' > $@
+		sed -e 's,^$(WM_PROJECT_DIR)/,$$(WM_PROJECT_DIR)/,' \
+			-e 's,^$(WM_THIRD_PARTY_DIR)/,$$(WM_THIRD_PARTY_DIR)/,' > $@
 
 #------------------------------------------------------------------------------